GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2001 🢒 Safari - 4WD 🢒 Body and Accessories 🢒 Keyless Entry 🢒 Keyless Entry System Description and Operation

The keyless entry system is a supplementary vehicle entry device. Use the keyless entry system in conjunction with a door lock key. Radio frequencies or discharged batteries may disable the system.

Keyless entry allows you to operate the following components:

    • The door locks
    • The illuminated entry lamps
    • The panic alarm (instant alarm)

The keyless entry system has the following main components:

    • The transmitters
    • The remote control door lock receiver (RCDLR)

The RCDLR communicates with the body control module (BCM) through the keyless entry serial data circuit. When you press a button on a transmitter, the transmitter sends a signal to the RCDLR. The RCDLR sends a lock, unlock, or panic alarm request to the BCM depending on which button is pressed on the transmitter. The BCM receives the message from the RCDLR and performs the appropriate function.

Unlock Driver's Door Only

Momentarily press the UNLOCK button in order to perform the following functions:

    • Unlock the driver door only.
    • Illuminate the interior lamps for approximately 40 seconds or until the ignition is turned ON.
    • Flash the exterior lights.
    • Disarm the content theft deterrent (CTD) system (if equipped).
    • Deactivate the CTD system when in the Alarm Mode (if equipped).

Unlock All Doors (Second Operation)

Momentarily press the UNLOCK button a second time within 5 seconds of the first press in order to perform the following functions:

    • Unlock the remaining doors.
    • Illuminate the interior lamps for approximately 40 seconds or until the ignition is turned ON.
    • Flash the exterior lights.

Lock All Doors

Press the LOCK button in order to perform the following functions:

    • Lock all of the doors.
    • Immediately turn off the interior lamps.
    • Flash the exterior lights.
    • Arm the content theft deterrent (CTD) system (if equipped).

Lock All Doors (Second Operation)

Momentarily press the LOCK button a second time within 5 seconds in order to perform the following functions:

    • Flash the exterior lights.
    • Chirp the horn.

Alarm

A single press of the panic button performs the following functions:

    • Illuminates the interior lamps.
    • Pulses the horn.
    • Flashes the exterior lamps for 30 seconds or until the following conditions occur:
       - The panic button is pressed again.
       - The ignition switch is turned to the RUN position with a valid key.

Rolling Code

The keyless entry system uses rolling code technology. Rolling code technology prevents anyone from recording the message sent from the transmitter and using the message in order to gain entry to the vehicle. The term "rolling code" refers to the way that the keyless entry system sends and receives the signals. The transmitter sends the signal in a different order each time. The transmitter and the RCDLR are synchronized to the appropriate order. If a programmed transmitter sends a signal that is not in the order that the RCDLR expects, then the transmitter is out of synchronization. This occurs after 256 presses of any transmitter button when it is out of range of the vehicle.